1. Field of the Invention
The present invention relates to systems and methods of transmitting and receiving audio/visual information, and in particular to a method and system allowing a user to remotely determine the strength of a signal received on an antenna.
2. Description of the Related Art
Traditionally, television programming has been delivered to viewers at home by very high frequency (VHF) and ultra high frequency (UHF) transmission from local broadcasting facilities. In the 1980s, dish antennas and receivers became available, allowing home viewers to receive television programming directly from satellite transmissions. Typically, however, these dish antennas were large and unsightly, and required professional installation. In the 1990s, satellite television service evolved to include smaller dish antennae and specially designed receivers. These smaller dish antennae are visually unobtrusive and can be installed by the viewer.
After the dish antenna is secured to a mounting, it must be aligned. This involves physically boresighting the antenna so that its sensitive axis is directed at the broadcasting satellite. Since the user cannot determine the precise location of the broadcasting satellite and because reasonably precise pointing is required, this task cannot be accomplished by simply visual boresighting. Instead, the strength of the signal from the satellite is measured and an indication of the signal strength is presented to the installer. In many cases, this involves a graphical and/or aural depiction of a relative received signal strength presented by an attached display device, such as a television.
The problem with the foregoing method is that the antenna and the television are typically separated by a substantial distance. Often, the antenna is installed on the roof of the home or on an outside wall, while the television is inside the home. In such cases, the antenna boresighting operation requires either two persons to complete, or requires that the installer travel back and forth between the antenna and the television several times, while trying to adjust the antenna for maximum signal reception.
In other devices, a visual indication is presented at a low noise block converter (LNB) of the satellite antenna. Circuits incorporated into the LNB measure the relative strength of the signal at the LNB and provide a visual indication of that signal. This is implemented, for example, by a variable duty cycle drive coupled to an output light emitting diode (LED), thus presenting a flashing rate to the user corresponding to the signal strength at the LNB. The user can then boresight the antenna by angularly displacing the antenna to maximize the strength of the received signal.
The problem with this method is that the LNB is typically capable of less precise measurements than are provided by circuits in the set top box. Further, some signal quality measurement parameters, such as bit error rate, or multipath distortion, cannot be measured at the LNB without substantial modifications. Moreover, more complex aiming algorithms utilizing outputs from multiple LNBs (e.g. for receiving signals from multiple satellites) cannot be supported by this approach.
What is needed is a system that allows precision antenna orientation adjustments to be made by a single user without making several trips to the television. The present invention satisfies that need.